Steve Baur
Former Editor, Modified Mustangs & Fords
October 13, 2010

If you've been around the Mustang scene for a while, you've probably heard of Fuel Air Spark Technology (FAST), or at least the aftermarket engine management system from the same company. Several years ago, Comp Cams acquired FAST, and the division's latest version of its engine management system became known as XFI.

While the XFI engine management system is a top-of-the-line piece, it requires a trained and skilled tuner to properly manipulate the software. The XFI system also has a price point to match its plethora of capabilities. FAST realized that there are far more do-it-yourselfer's with 400-500hp machines than there are racers with 2,000hp powerplants, and to fill this niche, it came up with the EZ-EFI system.

The FAST EZ-EFI system requires no previous fuel injection tuning experience, and you don't need a laptop computer to run the software. In fact, the EZ-EFI system performs its own tuning for you using an included wide-band O2 sensor.

The EZ-EFI system is available in a number of configurations, but the one that piqued our interest was the multi-port retrofit EFI kit (PN 302000). This retrofit kit is designed for use with the Ford EEC-IV 5.0L engine and other EFI applications, like GM's TPI setup. If you use FAST's XIM ignition module (PN 301313), you can install it on any Ford modular engine as well.

According to FAST, the EZ-EFI system will fire up to eight high-impedance injectors in applications ranging from street to full-on high performance. A simple yet capable handheld unit controls the system and provides on-board diagnostics, as well as a "check engine" LED display for maximum safety.

The included multi-port wiring harness is pre-wired for the most common GM sensors (yes, you'll have to run some GM parts on your car) and is fully labeled for an easy installation. FAST also offers a complete line of sensors, injectors, and adapters for other brands. The retrofit kit includes the self-tuning ECU, a wide-band O2 sensor with fitting and plug, a handheld user interface, a tachometer adapter, the multi-port wiring harness, and everything else you need for a quick and easy installation. FAST requires a vacuum-referenced fuel pressure regulator, like the factory Ford piece, with this system-one is available separately (PN Comp Cams 307030)-and a return-style fuel system.

At $875.99, the EZ-EFI system is not that inexpensive, but if you had to pay someone to tune your car, you'd be looking at anywhere from $500 to$1,000, depending on the engine management system you use. The EZ-EFI tunes itself and will tune for future modifications, whether you bolt on a set of headers or swap in an entirely different engine.

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"Current mass air systems do offer some leeway in regards to modifications, but nowhere near what this system can handle," says Comp Cams Ron Turnpaugh. "We've run it on a 252ci six-cylinder, then on a 350ci small-block, and then on a 570ci big-block without doing anything other than going back through the handheld's wizard and answering the questions. Horsepower ranged from 150 to 659-that's impressive," exclaims Turnpaugh. "This unit uses a wideband sensor, which the OEMs don't. It also stays in closed loop at wide open throttle, which a lot of the OEMs don't do since they can't monitor at that point with a narrow band sensor."

The benefit of running in closed loop at WOT is that you can maintain the target air/fuel ratio correctly. The older systems like the Ford EEC-IV just default to a fuel table that has a fuel curve based off of wide-band testing.

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